<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .para {
            width: 100px;
            height: 100px;
            border: 1px solid #000;
        }
        
        p:empty {
            background-color: red;
        }
        
        input:focus {
            background-color: orange;
        }
        
        input:disabled {
            background-color: #ccc;
        }
        
        input:enabled {
            border: 1px solid rgb(247, 31, 31);
        }
        
        input:checked+span {
            color: red;
        }
        /* 根元素 相当于HTML */
        
         :root {
            font-size: 28px;
        }
    </style>
</head>

<body>
    <p class="para"></p>
    <p class="para"></p>
    <p class="para">123</p>
    <p class="para"> </p>

    <p>
        <input type="text">
        <input type="text" disabled>
        <input type="text" disabled>
        <input type="text">
    </p>

    <p>
        <input type="checkbox"> 小王<span>123</span>
        <input type="checkbox"> 喜欢<span>123</span>
        <input type="checkbox"> 王者<span>123</span>
        <input type="checkbox"> 荣耀<span>123</span>
    </p>
</body>

</html>